This invention relates to a semi-automatic scanner for ultrasonic flaw detection, and more particularly to a scanner which can satisfactorily perform also the inspection of a curved surface in a bent piping.
A conventional scanner or ultrasonic flaw detector is disclosed in Japanese Laid-open Patent Application No. 52-108874. The detector comprises a carriage travelling on a guide rail mounted on a pipe, a guide rod mounted on the carriage and extending in the axial direction of the pipe, an inspection arm mounted so as to move along the guide rod and extending perpendicularly to the surface of the pipe, and a probe mounted on the end of the inspection arm so as to contact the surface to be inspected. In the ultrasonic flaw detector, the probe suitably follows the surface of a straight pipe shown in FIG. 1 of the above mentioned document, through the peripheral movement of the carriage as well as the guide rod, the axial movement of the inspection arm, and the movement of the probe perpendicular to the surface to be inspected of the pipe. However in a case where the ultrasonic flaw detector is employed to inspect the curved surface part of a bent pipe, the probe does not properly follow the curved surface.
In pipings to be inspected in a nuclear power plant, there are more bent pipe portions than straight pipe portions and much time is needed for inspecting such a bent pipe portion. Therefore, there scanners or ultrasonic flaw are desired which can satisfactorily perform also the inspection of the curved surface portions of bent pipings.